1221221021211 has 10 divisors (see below), whose sum is σ = 1824293130572. Its totient is φ = 814147347420.

The previous prime is 1221221021173. The next prime is 1221221021219. The reversal of 1221221021211 is 1121201221221.

1221221021211 is a `hidden beast` number, since 1 + 221 + 2 + 210 + 21 + 211 = 666.

It is not a de Polignac number, because 1221221021211 - 2⁶ = 1221221021147 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1221221021219) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 7538401285 + ... + 7538401446.

Almost surely, 2^{1221221021211} is an apocalyptic number.

1221221021211 is a deficient number, since it is larger than the sum of its proper divisors (603072109361).

1221221021211 is an equidigital number, since it uses as much as digits as its factorization.

1221221021211 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15076802743 (or 15076802734 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 18.

Adding to 1221221021211 its reverse (1121201221221), we get a palindrome (2342422242432).

The spelling of 1221221021211 in words is "one trillion, two hundred twenty-one billion, two hundred twenty-one million, twenty-one thousand, two hundred eleven".